Glossary
- V's

Van
der Waals force an attractive force between two atoms due
to a fluctuating dipole moment in one molecule inducing a dipole moment
in the other molecule which then interact.

Vapor
pressure the pressure of the vapor in equilibrium with its
liquid or solid phase.

Virtual
leak (sc) an “apparent” leak in a vacuum system
that is often traceable to some internal release of occluded and/or
sorbed gases.

Viscoelasticity
(r) a combination of viscous and elastic properties in a
material with the relative contribution of each being dependent on
time, temperature, stress and strain rate. Viscosity the resistance
of a material to flow under stress.

Viscosity,
Mooney (r) a measure of the viscosity of a rubber or rubber
compound determined in a Mooney shearing disk viscometer.

Void,
cellular material (r) a cavity unintentionally formed in
a cellular material and substantially larger than the characteristic
individual cells.

Volatilization
also known as vaporization, the conversion of a chemical substance
from a liquid or solid state to a gaseous or vapor state.

Volt
a unit of electromotive force or difference in electric potential.

Volume
swell (r) the increase in dimension caused by the absorption
of a fluid.

Vulcanizate
(r) the product of vulcanization, a cross-linked rubber.

Vulcanization
(r) an irreversible process during which a rubber compound, through
a change in its chemical structure (for example, cross-linking), becomes
less plastic and more resistant to swelling by organic liquids, while
elastic properties are conferred, improved, or extended over a greater
range of temperature.

Vulcanizing
system (r) the combination of a vulcanizing agent and, as
required, accelerators, activators and retarders used to produce the
desired vulcanization characteristics or vulcanizate characteristics.

(sc)
This term is generally associated with the semiconductor industry.